Core: Export Core::executePluginInstallWizard

ExtensionManager wants to execute the wizard, but it lives in another
plugin.

This change exports the former Core::PluginInstallWizard::exec as
Core::executePluginInstallWizard

Change-Id: I3ba068e9c8351355abfedfb9f6d6879de55b0534
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/plugininstallwizard.h

@@ -3,18 +3,14 @@
 
 #pragma once
 
+#include "core_global.h"
+
 #include <utils/filepath.h>
 
 #include <QCoreApplication>
 
 namespace Core {
-namespace Internal {
 
-class PluginInstallWizard
-{
-public:
-    static bool exec(const Utils::FilePath &archive = {});
-};
+CORE_EXPORT bool executePluginInstallWizard(const Utils::FilePath &archive = {});
 
-} // namespace Internal
 } // namespace Core